We normally see different variants assigned to different case materials/colors and the referenced ad does not specify if "AQ" designates yellow or white gold. I wonder if this watch has had a re-dial or alteration; the Selfwinding mark looks out of place, too low and not sharply printed, and different from Jabs' watch.

I was also thinking it had been redialed but I haven't taken it apart to see if it had any marks indicating this.I also have an example of a yellow gold case but that one is a basket case in need of a lot of parts and tender loving care.